A little graph help please

Hi guys, I'm a High School student seeking help. The regular physics help forum suspended my IP address from logging on for some reason, so no matter how many accounts I make, it wont let me sign in.

Okay, so my question is: given the picture below, how can I find the area below the graph (in the shaded region) ? It's for a lab that I did in class, but it wasn't until i finished the whole picture that i realized that I didn't know how to calculate the area of this graph.